Automatic stoker



May 19, 1931. i A, 1, gNow 1,805,641

AUTOMATIC STOKER Filed May 9, 1927 i INVENTOR WYITN Ess AZEXANDER [I Show ATTOR EY PatentedMay 19, 1931 UNITED, STATES PATENT OFFICE ALEXANDER I. SNOW, or woacEsrEp, massacnusn'r'rs, ASSIGNOR TO RILEY STOKER conroaarron, or WORCESTER, uessacnusar'rs, a CORPORATION or MASSACHU- SETTS AUTOMATIC STOKER Application filed Iay 9, 1927. Serial No. 189,905.

This invention relates to automatic stokers, and more particularly to means for controlling the air flow to the fuel supporting surfaces thereof.

p In an automatic stoker which is arranged to introduce fuel into the front part of a furnace and transport it progressively towards an ash dump at the rear of the furnace, the air requirements of any particular portion of the'fuel bed vary according to its distance from the point of entrance. This has been recognized, but various difiiculties have been encountered-in attempting to provide a suitable air control, particularly with stokers of the multiple retort underfeed type.

' The use of partitions or other obstructions in the airchamber beneath the retorts is undesirable because they make it difficult to remove the siftings which accumulate. In stokers of the t e shown in the U. S. patent to Riley No. 1, 90,651 various parts of the fuel supporting structure are reciprocated and the problem of roviding suitable air zoning in such a StOEGI is thereby complicated. Similar problems are encountered in other types of stokers'in which reciprocating air delivery means'are utilized. 1 I

It is accordingly one object of my invention to overcome such difiiculties and to provide, in connection with a multiple-retort underfeed stoker, a simple and convenient mechanism for controlling the air flow from front to rear of the stoker without obstructing materially the air chamber'beneath, and particularly to provide an arrangement for controlling theair flow to reciprocating air distributing members as used in-automatic stokers of various types. Further objects will not affect the regulation of the air flow. With these and other objects in view as will be apparent to those skilled in the art, my invention resides in the combination of parts set forth in the specification and covered by the claims appendedhereto.

In accordance with my invention, I rovide for localized air zoning in a sto er, whereby air is admitted to local groups of one or a few tuyere blocks, two being illustrated,'so that air may be admitted to each group through. separately controlled channels, whether used for feeding air to the same retort or to the corresponding tuyere blocks across the stoker, andI so arrange the parts that the air may be separately controlled in parallel zones extending at right angles to the retorts. This invention particularly contemplates localized air zoning to the tuyeres blocks mounted in reciprocable side bars in a stoker of the Riley type.

In one embodiment of my. invention, I pro-' vide a stoker having a plurality of underfeed.

retorts arranged parallel to each other and extending from front to rear of a furnace.

To provide for localized air zoning, the longitudinally extending side bars or members which form the sides of the retorts may be formed hollow and left open at the bottom to permit the entrance of air from a suitable air chamber beneath the stoker. The tuyere blocks which are arran ed to form a support for the. fuel bed and ist-ribute air thereto may be of any suitable construction and are mounted on top of the hollow side bars. The

space within each side bar is'divided into a number of separate air passages by means of a plurality of partitions extending trans versely of the side bar and preferably in substantially vertical planes. By means of this 7 construction, it is apparent that each air passage will deliver air to a comparatively small localized group'of tuyere blocks. I arrange a suitable damper device for controlvices in the different side bars may ing-shown in section on the line 1-1 of Fig. 3;

ig. 2 is a partial section on the line 2-2 of Fi 1, parts being broken away;

ig. 3 is a similar view on the line 33 of Fig. 1;

a Fig. 4 is a section on the line 4-4 of Fig. 3, a part only of the stoker being shown; and

Fig. 5 is a perspective view of a damper device and its controlling member.

In-the drawings I have illustrated my invention as applied to a stoker of the multi leretort underfeed type. This comprises a uel hopper of suitable construction which is mounted adjacent to a vertical front wall 11 of a furnace. Mounted beneath the hopper and arranged to receive fuel therefrom are a l-uralit-y of horizontal cylindrical ram ca..-

mgs 12. A suitable ram, not illustrated, is

arranged to be reciprocated within each ram case by a rotatable crankshaft 14, as is well known in this art. This crankshaft is are ranged to be rotated at a slow speed through.

- a suitable gear reduction device 16 which is etructed for horizontal reciprocation.

q forwar connected toa desired source of power. The

weight of the ram casing and associated parts may be supported on pipe columns 17 which rest on a concrete floor 18.

A plurality of parallel underfeed retorts 20 extend rearwardly from the front wall 11. These retorts are provided with stationary bottom lates 21 which incline downwardly at a sli ii nace. e sides of the retorts are formed by the side bars 24 which are arranged to sup rt on their u per surfaces the tuyere blocks These tuy re blocks may be arranged in. asteplike formation as illustrated in rows extending longitudinally of the stoker between citedby'its corresponding ram through a lost motion connection in a manner well known and fully disclosed in the petent t angle towards the rear of the furto Riley No. 1,090,651. At its lower and rearward end, each side bar is attached to a shoe 32 arranged to slide over the upper plane surface of a base plate 33 which is bolted to a pair of I-beams 35. beams extend transversely of the stoker and rest in suitable pockets in the side wall of the furnace as will be well understood.

I prefer to provide an overfeed grate section 36, which may be of any suitable construction and which is mounted on the side bars 24 beneath the lower end of the retort 20. This overfeed grate serves as a tuyere structure to furnish air for the combustion of any unconsumed coke which issues from the lower end of the underfeed retort.

In the rear of the overfeed-grate 36 I have illustrated one form of rocker grate member 38 which is preferably pivotally connected to the shoe 32 as described in the patent to Riley et al. No. 1,605,665. If desired, the upper portion of this rocker plate 38 ma be a hollow construction as illustrated an rovided with air openings to assist in burning out any combustible remaining in the ash and refuse-supported thereon. The rocker plates rest at their lower ends on rolls 40 suitably mounted at the rear ends of horizontal rack bars 41. A vertical bridgewall 4:3 is arranged in the rear of the rocker plates and in substantial proximity thereto. The position of the rocker plates 38 in relation to the bridgewall may be adjusted by means of a horizontal shaft 45, mounted 1n suitable brackets 46 which are bolted to the forward I-beam 35. This shaft carries a series of pinions 48 which mesh with the teeth on the rack bars. It will be understood that the shaft extends through the side walls of the furnace and is arranged to be controlled from a convenient point. 7

A suitable vertical plate 50 is mounted beneath the front wall 11 of the furnace so as to entirely enclose the space beneath the stoker retorts and form a pressure chamber 52. Air may be supplied to this pressure chamber from any suitable forced draft apparatus, such as a fan, throu h a duct 53 which may be provided wit a suitable dam r 54. Air is' delivered to the tuyere bloc s 25 and overfeed grates 36 from the air chamber 52 throu h the side bars 24, which, as shown cleary in Figs. 2 and 3, are of hollow construction.- The air for the rocker dump plates 38 passes through the H base plates 33and shoes 32, as shown clearly in Fig. 1, and this airmay be'controlled if desired by dampers 54 mounted on a horizontal rotatable shaft 55 which, it will be understood, extends throu h the side wall and I can be'controlled from t e outside of the furnace.

These 1- ioo which is discharged at the rear. For this reason the character of the fuel bed is constantly changing and the requirements as to air pressure and volume are different at each stage of combustion. These changes are very marked and a decided difference in air pres= sures and volume at each point along the grate surface is frequently necessary. Moreover the requirements of air pressure and distribution vary widely for different fuels and with different rates of combustion.

In order to provide a construction by means of which the air flow to different parts of the fuel bed may be conveniently controlled by the stoker operator without the necessity of complicated dividing walls which obstruct the air chamber beneath the stoker. and make it extremely difiicult to remove siftings therefrom, I arrange within the interior of each hollow side bar 24 a series of transverse partition walls 58 which are shown 'clearly in Fig. 4. These walls 58 are preferably arranged in vertical planes as illustrated, as this construction permits any fine coal which may sift through the openings in the tuyere blocks to fall freely into the air chamber. 52, rather than obstruct theair passages as would otherwise occur.

' It will be seen from an inspection of Fig. 4,

that this construction provides a series of localized air passages through the side bars which connect with a comparatively small portion of the fuel supporting surface. I

have shown'one passage as leading to the overfeed grate section 36 and a separate passage leading to each pair of tuyere blocks 25. Withthis construction, each row of tuyere blocks is divided by the partitions into 10- calized groups consisting of pairs of tuyere blocks. It is, however, apparent that there maybe more or less of these partition walls '58 depending upon the degree of air control which is desired and each passage may supply air to one or more tuyere blocks in such localized groups.

Each airpassage through the side bars 24 is provided with a suitable damper, which in the embodiment illustrated comprises a substantially fiat rectangular plate 60 provided on its uppersurface with a pair of upstanding lugs 61 having holes 62 there-' through The lugs 61 are arranged off cen ter on the plate 60 for a purpose which will be described later. Each damper plate 60 is pivotallymounted in the side bars on a horiby a rod or bar 67 which is arranged parallel totherod64. 1 i

In order to permit simultaneous adjustment of the correspondingly located dampers in the different sides bars, and thus formj parallel air zones extending laterally of the retorts, I provide a suitable connecting member arranged transversely of the stoker. In the embodiment illustrated, this member comprises an angle 70 in one leg ofwhich a seriesof notches 71 are provided. As shown each notch 71 is arranged to, fit over one of thedamper rods 67. As heretofore described, the lugs 61 on the damper plates are arranged off center and this causes each damper to be unbalanced so that it tends to close by its own weight. There is a particular advantage in this form of construction due to the fact that considerable expansion takes place in a stoker because of the heat of the furnace and this. is particularly apparent in a wide stoker. By making the rods 67 fit rather loosely in the notches 71 it is apparent that the dampers 60 will all close by their own weight regardless of any expansion which may take place in the stoker structure, The angle 7 O is affected very little by the heat of the furnace as it is subjected to the air flow through the. chamber '52 and for this reason if the dampers 60 were balanced and the notches 71 were made a tight fit, it would result from expansion of the stoker that certain dampers might be closed while others connected thereto would be partially open.

In Fig. 2 I have illustrated one simple means for controlling the position of the angles 7 O and hence the opening of the dampers connected thereto. Each angle 70 has mounted thereon a small dependin lug 75 to which is pinned a connecting link 76 which extends horizontally through a small opening 7 8 in the side wall 80 of the furnace. A substantially vertical lever 82 is pivotally mounted in a bracket 83 on the outside of the fur- .nace side wall and is pinned to the outer end of the link 76. An arc-shaped member 85 may be mounted on the outside of the furnace wall in a suitable position and the lever 82 may be clamped thereto at any desired point of adjustment by means of a thumb screw 86. It will be understood that there is alever 82 provided for each zone of the stoker, there being seven of these zones in the stoker illustrated, exclusive of the rocker dump plates38. In the case of an exceptionally wide stoker, such; as for example a stoker having sixteen retorts, it may be desirable to' be apparent from the above disclosure. Coal is delivered'to the underfeed retorts 20 from the hopper 10 by the reciprocating rams and v the fuel bed is carried rearwardly towards passes out of the lower en of the retorts and moves over the reciprocating overfeed ates 36 and dump plates 38 to the ash pit. t will be understood that the different side bars in the stoker are moving in different but parallel directions at the same time and as a result -the rods 67 on the dampers slide relative to the control members which remain stationary except when it is necessary to make an adjustment by means of the corresponding lever 82. The air flow to any particular section of the fuel bed in relation to other sections may be conveniently controlled from an accessible point outside the stoker. This makes the operation of the stoker extremely flexible and adaptableto different rates of combustion and different types of fuel. By removing the front plate 50 or a small section thereof, it is a simple matter to obtain access to the air chamber 52whenever it be comes necessary to remove therefrom an accumulation of fine coal or siftings. This air chamber is entirely unobstructed and no difficulty is encountered in effecting such removal. It is to be understood that the damper 54 will be utilized for varying the pressure in the air chamber 52 to take care of changes in the rate of burning fuel and that the dampers 60 will be utilized merely for lv)a(1i'ying the distribution of air to the fuel Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. A stoker comprising a movable support for the fuel arranged to admit air thereto, said support including walls forming an air passage, an adjustable damper movable with said walls to control the air flow, and a stationary member adjustably mounted to vary the adjustment of the damper as desired.

'2. A stoker comprising a reciprocable structure arranged to form a support for the fuel bed and deliver air thereto for combustion, said structure including walls so constructed as to form an air passage,-a damper mounted in said air passage and arranged for pivotal adjustment about an axis extending in the direction of reciprocation, and a stationary member adjustably mounted for controlling the adjustment of the damper.

3. A stoker comprising a reciprocable structure arranged to form a fuel supporting and air admitting surface, said structure including walls so constructed as to form an air passage, a damper mounted in said passage and arranged for pivotal adjustment about an axis extending in the direction of reciprocation, a rod mounted on said damper parallel to said axis and spaced therefrom, and a stationary adjustable member arranged to cooperate with said'rod in .varyin the adjustment of the damper, said ing arranged to reciprocate with the damper relative to the adjusting member.

4. A stoker comprising a plurality of structures arranged to form a fuel supporting and air admitting surface, means for reciprocating said structures relative to each other in parallel directions, each of said structures includin walls reciprocable therewith and arrange to form an air passage, a dam er mounted in each passage control the ow of air therethrough, and a stationary ad'ustable member extending transversely o the direction of reciprocation and arranged to simultaneously adjust the position of a plurality of said dampers irrespective of the relative positions of said structures.

5. A stoker comprising a plurality of "structures arranged to form a fuel supporting and air admitting surface, each structure including walls arranged to form an air passage, a damper pivotally mounted in each passage to control the flow of air therethrough and so arranged that it will tend toclose, and an adjusting member arranged to simultaneously adj ust a plurality of the dampers, said member being loosely connected to the dampers.

6. A stoker comprising a plurality of structures arranged to form a fuel supporting and air admitting surface, each structure including walls arranged to form an air passage, a damper pivotally mounted in each passage about an axis spaced from its center of gravity so that the dam er will tend to close by its own weight, an a member arran d to simultaneously adjust a plurality o nected to the dampers. v

7. An underfeed stoker comprising separately reciprocable hollow side bars and bot-. toms forming parallel retorts, a row of tuyeres for each side bar, partitions within the side bars forming separate air passages and dampers mounted on the side bars to control the flow of air in said passages.

8. An underfeed stoker comprising spaced walls defining parallel retorts, a row of tuyere blocks spanning the space between each pair of adjacent retort walls and extending lengthwise of the retorts, means forming separate air passages to localized groups of the tuyeres in each row, and a separate regulatable control device for each of said groups so that the air pressure to one of said groups may be regulated independently of that to another of the groups in the same row.

said. .dampers, said, member being loosely con- 9. An underfeed stoker comprising spaced flow in each passage independently of other passages in the same row, and connections to operate together those dampers which control the air flow to tuyere groups arranged laterof, means forming a chamber for airunder pressure beneath said retorts, means forming separate air passages between adjacent retort walls leading from said air chamber to localized groups of tuyere blocks, means adjacent to one or" said passages to control the air pressure therein independently of the air pressure in another of said passages in the same row, and means for operating said control means from a point outside chamber. I

11. An underfee'd stoker comprising walls forming spaced parallel retorts, rows of tuyere blocks mounted on said walls between the retorts and extendin lengthwise thereof, means forming a cham er for air under pressure beneath said retorts, means forming independent air passages between adjacent retort walls leadin from said chamber to localized groups 0 tuyere blocks in each row, a damper mounted adjacent to each of said passages to control the airflow therethrough, and means for controlling the position of one of said dampers from a point outside of said air chamber independently of another of said dampers which is connected with tuyere blocks in the same row.

12. An underfeed stoker comprising a pluof said air rality of hollow side bars arranged parallelto each other and spaced apart to form retorts ther betweem-tuyere blocks mounted on the side bars, means forming an air chamber for the ,antroduction of air under pre sure beneath the side bars, partitions in the side bars arranged to providea piurality of independent air passages through each side bar, dampers mounted in certain of said air passages to control the fiow of air to the tuyeres connecting therewith, and means for s1multaneously operating correspondingly located dampers in difi'erent sidebars independently of other dampers, whereby the air flow maybe controlled in zones extending transversely of the retorts.

13. An underfeed stoker comprising a plurality of hollow reciprocable side bars arof May, 1927 means for simultaneously adjusting correspondingly located dampers in difierent side bars. e I

14. An underfeed stoker comprising a plurality of hollow reciprocable side bars arranged parallel to each other and spaced apart to form retorts therebetween, tuyere blocks mounted on the side bars, means forming an air chamber for the introduction of air under pressure beneath the side bars, partitions in the side bars arranged to form a 4 plurality of independent air passages through each side bar, a damper pivotally mounted in each air passage about an axis extending in the direction of reciprocation, said dampers being reciprocable with the side bars, and an adjusting member extending transversely of the retorts and arranged to simultaneously adjust corres ondingly located dampers in different side bars.

15. An underfeed stoker comprising asplurality of hollow reciprocable side bars arran ed parallel to each other and spaced apart to orm retorts therebetween, tuyere blocks mounted on the side bars, means forming an air chamber for the introduction of air "under pressure beneath the side bars, substantially vertical partitions in the side bars arranged to-form a plurality of independent air passages through each side bar, a damper pivotally mounted in each air passage about an axis extending in the direction of reciprocation, said damper being reciprocable with its bar, a rod mounted on each damper parallel to said axis and spaced therefrom, stationary adjustable members extending transversely of the retorts and connecting the correspondingiy located rods at the different side bars, and means for adjusting each member in dependentiy of the others from a point outside the air chamber.

16. A stolnr comprising a plurality of parallel bars having: tuyere blocks thereon and reciprocable ongitudinally in different but parallel directions at the same time, means including dampers movable with said bars arranged to control the air flow to the tuyere blocks, and means to simultaneously operate a group of dam ers in a row extending transversely of the ars irrespective of the relative positions of the bars.

Signed at Worcester, Mass., this fifth day I ALEXANDER I. SNOW.

blocks mounted on the side bars, means forming an air chamber for the introduction of air under pressure beneath the sidebars, partitions in each side bar arranged to provide a. plurality of independent air passages therethrough, a damper mounted in each air passage and reciprocable with the side bar, and

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